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@navanathjadhav

navanathjadhav/pager.service.ts Secret

Created Dec 25, 2020
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3. Calculate pager data required for showing pages
getPager(totalItems: number, currentPage: number = 1, pageSize: number = 10) {
// calculate total pages
let totalPages = Math.ceil(totalItems / pageSize);
// ensure current page isn't out of range
if (currentPage < 1) {
currentPage = 1;
} else if (currentPage > totalPages) {
currentPage = totalPages;
}
let startPage: number, endPage: number;
if (totalPages <= 10) {
// less than 10 total pages so show all
startPage = 1;
endPage = totalPages;
} else {
// more than 10 total pages so calculate start and end pages
if (currentPage <= 6) {
startPage = 1;
endPage = 10;
} else if (currentPage + 4 >= totalPages) {
startPage = totalPages - 9;
endPage = totalPages;
} else {
startPage = currentPage - 5;
endPage = currentPage + 4;
}
}
// calculate start and end item indexes
let startIndex = (currentPage - 1) * pageSize;
let endIndex = Math.min(startIndex + pageSize - 1, totalItems - 1);
// create an array of pages to ng-repeat in the pager control
let pages = Array.from(Array(endPage + 1 - startPage).keys()).map(i => startPage + i);
// return object with all pager properties required by the view
return {
totalItems: totalItems,
currentPage: currentPage,
pageSize: pageSize,
totalPages: totalPages,
startPage: startPage,
endPage: endPage,
startIndex: startIndex,
endIndex: endIndex,
pages: pages,
};
}
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